Cephalexin 250mg/5ml Susp 100ml
It is used to treat bacterial infections.
Drug Class
Antibiotic
Pharmacologic Class
First-generation cephalosporin
Pregnancy Category
Category B
FDA Approved
Jan 1971
DEA Schedule
Not Controlled
Overview
What is this medicine?
Cephalexin is an antibiotic medication used to treat various bacterial infections, such as those affecting the skin, ears, throat, and urinary tract. It works by stopping the growth of bacteria.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. If you experience stomach upset, taking it with food may help. Continue using the medication even if your symptoms improve.
Before taking a dose, shake the liquid medication well. Measure liquid doses carefully using the measuring device that comes with the medication. If no device is provided, ask your pharmacist for a suitable measuring tool.
Storing and Disposing of Your Medication
Store the medication in the refrigerator and discard any unused portion after 2 weeks. Keep the lid tightly closed and store all medications in a safe place, out of the reach of children and pets.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. If you experience stomach upset, taking it with food may help. Continue using the medication even if your symptoms improve.
Before taking a dose, shake the liquid medication well. Measure liquid doses carefully using the measuring device that comes with the medication. If no device is provided, ask your pharmacist for a suitable measuring tool.
Storing and Disposing of Your Medication
Store the medication in the refrigerator and discard any unused portion after 2 weeks. Keep the lid tightly closed and store all medications in a safe place, out of the reach of children and pets.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses.
Lifestyle & Tips
- Take the medication exactly as prescribed by your doctor, even if you start feeling better. Do not skip doses or stop taking it early, as this can lead to the infection coming back or becoming harder to treat.
- Cephalexin can be taken with or without food. If it causes stomach upset, try taking it with food or milk.
- Shake the oral suspension well before each use. Use a measuring spoon or cup to ensure the correct dose.
- Store the liquid medication in the refrigerator and discard any unused portion after 14 days (or as directed by the pharmacist).
- Avoid alcohol consumption while taking antibiotics, as it may worsen side effects like stomach upset.
Available Forms & Alternatives
Available Strengths:
- Cephalexin 250mg/5ml Susp 100ml
- Cephalexin 250mg/5ml Susp 200ml
- Cephalexin 125mg/5ml Susp 100ml
- Cephalexin 125mg/5ml Susp 200ml
- Cephalexin 250mg Capsules
- Cephalexin 500mg Capsules
- Cephalexin 250mg Tablets
- Cephalexin 500mg Tablets
- Cephalexin 750mg Capsules
- Cephalexin 125mg/5ml Susp 100ml
- Cephalexin 500mg Tablets
- Cephalexin 250mg Tablets
Dosing & Administration
Adult Dosing
Standard Dose:
250 mg to 1 g every 6 hours, or 500 mg every 12 hours, depending on infection severity and type.
Dose Range:
250 - 1000 mg
Condition-Specific Dosing:
mildToModerateInfections:
250 mg every 6 hours or 500 mg every 12 hours
severeInfections:
500 mg every 6 hours or 1 g every 6 hours
skinAndSoftTissueInfections:
500 mg every 12 hours
streptococcalPharyngitis:
250 mg every 6 hours or 500 mg every 12 hours for 10 days
urinaryTractInfections:
250 mg every 6 hours or 500 mg every 12 hours
Pediatric Dosing
Neonatal:
Not established (use with caution, consult specialist)
Infant:
25-50 mg/kg/day in divided doses every 6 or 12 hours. For severe infections, up to 100 mg/kg/day.
Child:
25-50 mg/kg/day in divided doses every 6 or 12 hours. For severe infections, up to 100 mg/kg/day. Max 4 g/day.
Adolescent:
Same as adult dosing (typically >12 years or >40 kg)
Dose Adjustments
Renal Impairment:
Mild:
CrCl 30-59 mL/min: No dose adjustment typically needed, but consider extending dosing interval to every 8-12 hours for severe infections.
Moderate:
CrCl 15-29 mL/min: 250 mg every 8-12 hours.
Severe:
CrCl <15 mL/min: 250 mg every 12-24 hours.
Dialysis:
Hemodialysis: 250 mg initially, then 250 mg after each dialysis session. Peritoneal Dialysis: 250 mg every 12 hours.
Note:
Dose adjustments are based on creatinine clearance (CrCl). For severe infections, the maximum daily dose should be reduced accordingly.
Hepatic Impairment:
Mild:
No specific adjustment needed.
Moderate:
No specific adjustment needed.
Severe:
No specific adjustment needed.
Pharmacology
Mechanism of Action
Cephalexin is a first-generation cephalosporin antibiotic that inhibits bacterial cell wall synthesis. It binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. PBPs are enzymes involved in the final stages of peptidoglycan synthesis, which is crucial for maintaining the structural integrity of the bacterial cell wall. Inhibition of PBPs leads to defective cell wall formation, increased osmotic pressure, and ultimately, bacterial cell lysis and death.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 90%
Tmax:
Approximately 1 hour (fasted state)
FoodEffect:
Food may delay the rate of absorption (Tmax) but does not significantly affect the extent of absorption (AUC).
Distribution:
Vd:
Approximately 0.26 L/kg
ProteinBinding:
Approximately 10-15%
CnssPenetration:
Limited (does not achieve therapeutically effective concentrations in CSF unless meninges are inflamed)
Elimination:
HalfLife:
Approximately 0.5 to 1.2 hours (prolonged in renal impairment)
Clearance:
Primarily renal clearance
ExcretionRoute:
Renal (glomerular filtration and tubular secretion)
Unchanged:
Approximately 80% excreted unchanged in urine within 8 hours
Pharmacodynamics
OnsetOfAction:
Rapid (within hours of first dose)
PeakEffect:
Achieves peak plasma concentrations within 1 hour
DurationOfAction:
Approximately 6-8 hours (based on dosing interval)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of a severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis), such as:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in the mouth, throat, nose, or eyes
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Fever, chills, or sore throat
Unexplained bruising or bleeding
Feeling extremely tired or weak
Confusion
Hallucinations (seeing or hearing things that are not there)
Difficulty urinating or changes in urine output
Seizures
Severe dizziness
Severe headache
Severe joint pain
Vaginal itching or discharge
Diarrhea and Antibiotic Use
Diarrhea is a common side effect of antibiotics. In rare cases, a severe form of diarrhea called C. diff-associated diarrhea (CDAD) may occur. This condition can lead to a life-threatening bowel problem. If you experience any of the following symptoms, contact your doctor immediately:
Stomach pain
Cramps
Very loose, watery, or bloody stools
Do not treat diarrhea without consulting your doctor.
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people do not experience any side effects or only have mild ones. If you notice any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Stomach pain or diarrhea
* Upset stomach or vomiting
This is not a comprehensive list of all possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of a severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis), such as:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in the mouth, throat, nose, or eyes
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Fever, chills, or sore throat
Unexplained bruising or bleeding
Feeling extremely tired or weak
Confusion
Hallucinations (seeing or hearing things that are not there)
Difficulty urinating or changes in urine output
Seizures
Severe dizziness
Severe headache
Severe joint pain
Vaginal itching or discharge
Diarrhea and Antibiotic Use
Diarrhea is a common side effect of antibiotics. In rare cases, a severe form of diarrhea called C. diff-associated diarrhea (CDAD) may occur. This condition can lead to a life-threatening bowel problem. If you experience any of the following symptoms, contact your doctor immediately:
Stomach pain
Cramps
Very loose, watery, or bloody stools
Do not treat diarrhea without consulting your doctor.
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people do not experience any side effects or only have mild ones. If you notice any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Stomach pain or diarrhea
* Upset stomach or vomiting
This is not a comprehensive list of all possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe diarrhea (watery or bloody stools), especially if accompanied by fever or abdominal cramps (may be a sign of C. difficile infection, seek medical attention immediately).
- Signs of an allergic reaction: rash, hives, itching, swelling of the face/lips/tongue/throat, difficulty breathing or swallowing (seek emergency medical attention).
- Unusual bruising or bleeding.
- Yellowing of the skin or eyes (jaundice).
- Dark urine or pale stools.
- Severe stomach pain or persistent nausea/vomiting.
- New or worsening vaginal yeast infection or oral thrush (white patches in the mouth).
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
If you are currently taking probenecid, as this may interact with the medication.
To ensure safe treatment, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your existing health problems
This information will help your doctor determine whether it is safe for you to take this medication in conjunction with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor to confirm that it is safe to do so.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
If you are currently taking probenecid, as this may interact with the medication.
To ensure safe treatment, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your existing health problems
This information will help your doctor determine whether it is safe for you to take this medication in conjunction with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor to confirm that it is safe to do so.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you are taking this drug for an extended period, your doctor may recommend regular blood tests to monitor your condition.
If you have diabetes and regularly test your urine for glucose, consult with your doctor to determine the most suitable testing method for you, as this medication may interfere with certain test results. Additionally, be sure to notify all your healthcare providers and laboratory personnel that you are taking this medication, as it may affect the accuracy of certain lab tests.
Do not take this medication for longer than prescribed, as this can increase the risk of a second infection. It is also crucial to discuss your pregnancy status or plans with your doctor, as well as whether you are breastfeeding, to carefully weigh the benefits and risks of this medication for both you and your baby.
If you have diabetes and regularly test your urine for glucose, consult with your doctor to determine the most suitable testing method for you, as this medication may interfere with certain test results. Additionally, be sure to notify all your healthcare providers and laboratory personnel that you are taking this medication, as it may affect the accuracy of certain lab tests.
Do not take this medication for longer than prescribed, as this can increase the risk of a second infection. It is also crucial to discuss your pregnancy status or plans with your doctor, as well as whether you are breastfeeding, to carefully weigh the benefits and risks of this medication for both you and your baby.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Epigastric distress
- Diarrhea
- Hematuria (blood in urine)
- Rarely, convulsions
What to Do:
In case of overdose, call your local poison control center (e.g., 1-800-222-1222 in the US) or seek emergency medical attention immediately. Treatment is primarily supportive; hemodialysis may be useful in severe cases.
Drug Interactions
Major Interactions
- Metformin (increased metformin levels, risk of lactic acidosis)
Moderate Interactions
- Probenecid (decreased renal excretion of cephalexin, increased cephalexin levels)
- Oral Contraceptives (theoretical risk of reduced efficacy, though clinical significance is debated)
- Warfarin (may enhance anticoagulant effect, monitor INR)
Minor Interactions
- Live Bacterial Vaccines (e.g., Typhoid vaccine - may reduce efficacy)
Monitoring
Baseline Monitoring
Renal function (serum creatinine, BUN, CrCl)
Rationale: To determine appropriate dosing, especially in elderly or renally impaired patients, as cephalexin is primarily renally eliminated.
Timing: Prior to initiation of therapy in patients with known or suspected renal impairment.
Allergy history
Rationale: To identify potential hypersensitivity reactions to cephalosporins or penicillins.
Timing: Prior to initiation of therapy.
Routine Monitoring
Signs and symptoms of infection resolution
Frequency: Daily
Target: Improvement in fever, pain, inflammation, etc.
Action Threshold: Lack of improvement or worsening symptoms may indicate treatment failure or resistant organism.
Renal function (serum creatinine, BUN)
Frequency: Periodically, especially during prolonged therapy or in patients with renal impairment.
Target: Within patient's baseline or acceptable limits.
Action Threshold: Significant increase may require dose adjustment or discontinuation.
Complete Blood Count (CBC) with differential
Frequency: Periodically, especially during prolonged therapy (e.g., >2 weeks).
Target: Within normal limits.
Action Threshold: Significant changes (e.g., eosinophilia, neutropenia, thrombocytopenia) may indicate drug-induced hematologic effects.
Liver function tests (ALT, AST, bilirubin)
Frequency: Periodically, especially during prolonged therapy.
Target: Within normal limits.
Action Threshold: Significant elevation may indicate drug-induced hepatotoxicity (rare).
Symptom Monitoring
- Rash, itching, hives (signs of allergic reaction)
- Diarrhea (especially severe or persistent, may indicate C. difficile infection)
- Nausea, vomiting, abdominal pain
- Oral thrush or vaginal yeast infection (signs of superinfection)
- Unusual bleeding or bruising (rare, but possible hematologic effects)
- Signs of kidney dysfunction (e.g., decreased urine output, swelling)
Special Patient Groups
Pregnancy
Cephalexin is generally considered safe for use during pregnancy (Pregnancy Category B). Animal reproduction studies have not shown a risk to the fetus, and there are no adequate and well-controlled studies in pregnant women, but human experience suggests low risk.
Trimester-Specific Risks:
First Trimester:
Low risk of teratogenicity based on available data.
Second Trimester:
Generally considered safe.
Third Trimester:
Generally considered safe.
Lactation
Cephalexin is excreted in low concentrations in human breast milk. It is generally considered compatible with breastfeeding (Lactation Risk L2). Monitor breastfed infants for potential gastrointestinal disturbances (e.g., diarrhea, candidiasis) or allergic reactions.
Infant Risk:
Low risk. Potential for minor GI upset (diarrhea) or sensitization in the infant.
Pediatric Use
Cephalexin is widely used and generally well-tolerated in pediatric patients. Dosing is weight-based. Safety and efficacy in neonates (<1 month) are not well-established, and use should be with caution and under specialist guidance.
Geriatric Use
No specific dose adjustment is required based on age alone. However, elderly patients are more likely to have decreased renal function, which necessitates dose adjustment based on creatinine clearance. Monitor renal function closely in this population.
Clinical Information
Clinical Pearls
- Cephalexin is a first-generation cephalosporin, primarily active against Gram-positive bacteria (e.g., Staphylococcus aureus, Streptococcus pyogenes) and some Gram-negative bacteria (e.g., E. coli, Klebsiella pneumoniae, Proteus mirabilis).
- It is a common choice for skin and soft tissue infections (e.g., cellulitis, impetigo), uncomplicated urinary tract infections, and streptococcal pharyngitis.
- Patients with a history of severe penicillin allergy (e.g., anaphylaxis) should generally avoid cephalexin due to potential cross-reactivity, although the risk is low (around 1-5%) for first-generation cephalosporins.
- Advise patients to complete the full course of therapy to prevent the development of antibiotic resistance.
- Oral suspension must be refrigerated and discarded after 14 days.
Alternative Therapies
- Amoxicillin (for susceptible infections)
- Amoxicillin/Clavulanate (Augmentin)
- Cefadroxil (another first-generation cephalosporin, often dosed once or twice daily)
- Clindamycin (for skin/soft tissue infections, especially if penicillin/cephalosporin allergy)
- Macrolides (e.g., Azithromycin, Clarithromycin - for respiratory tract infections, some skin infections, or in penicillin/cephalosporin allergy)
- Trimethoprim/Sulfamethoxazole (Bactrim - for UTIs, some skin infections)
Cost & Coverage
Average Cost:
Highly variable, typically low per 100ml suspension
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (preferred generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.